Frustrating bug with custom game creation

Since the new patch, this has been going on whenever I create a custom game. The above window pops up for about 20 seconds, and you have to wait until you can cancel it, and then proceed to cancel it before actually being able to start the game. This happens every single time I start a custom game, and it's very frustrating when I'm only starting one to see if I can or cannot play a real game. Please fix this, thanks!!